WO2017101285A1

WO2017101285A1 - Tracing method for distribution of mobile ions in ionic migration spectrometer

Info

Publication number: WO2017101285A1
Application number: PCT/CN2016/086617
Authority: WO
Inventors: 倪凯; 郭开泰; 余泉; 唐彬超; 余洲; 钱翔; 王晓浩
Original assignee: 清华大学深圳研究生院
Priority date: 2015-12-15
Filing date: 2016-06-21
Publication date: 2017-06-22
Also published as: CN105403614A; US10161904B2; US20170219524A1; CN105403614B

Abstract

A tracing method for distribution of mobile ions in an ionic migration spectrometer, comprising the following steps: firstly, selecting a sample that has a luminescent property as a tracing sample; secondly, ionizing the tracing sample with an electrospray ionization source (1), sending same to a drift tube of an ionic migration spectrometer, and collecting ions of the tracing sample at a cross section to be measured using an ion collecting and developing flat plate (3); and finally, treating the collected tracing particle ions to be measured on the collecting and developing flat plate (3) with an appropriate means, making the ions emit light, and displaying a distribution map of movement positions of the ions on the cross section to be measured. The luminescence tracing manner and charged ion movement under an ionic migration spectrometer are used in a combined manner, so that position distribution of charged ions under the ionic migration spectrometer can be mastered more visually and practically.

Description

Tracer method for moving ion distribution in ion mobility spectrometer

Technical field

The invention relates to an ion mobility spectrometer, in particular to a method for tracing a moving ion distribution in an ion mobility spectrometer.

Background technique

The problem of the movement of sample ions in the migration tube is an important part of the ion mobility spectrometer research. It is the basis for the design, performance exploration and improvement of the ion mobility spectrometer.

At present, when exploring the movement of sample ions in an ion mobility spectrometer, a mathematical model of the ion mobility spectrometer is usually established and the possible motion trajectories of the ions are calculated according to the theoretical formula. Today, computer performance is increasing. SIMION (an electrostatic lens analysis and simulation software) and other ion mobility spectrometer ion motion simulation software have been frequently used. Researchers can quickly and easily establish an electric field model in an ion mobility spectrometer through a computer. , to generate a corresponding ion motion trajectory cross-sectional profile of the specific sample particles at the initial velocity and the charge amount. But there is a difference between theory and practice. The theoretical ion trajectory cross-sectional distribution map can only guide the design and performance of the ion mobility spectrometer.

Faraday disk with micro-current amplifier is an ion detection method under atmospheric pressure, which uses the neutralization of charged particles on its surface to generate a reaction current, which is converted into a voltage signal by a micro-current amplifier. The ion detection system is often placed on an ion mobility spectrometer. End. However, in practical applications, if the Faraday disk is placed in the migration tube, it will not only affect the existing electric field, but also the total current caused by the ions on the surface of the Faraday disk at the same time.

Summary of the invention

The object of the present invention is to solve the problem that the motion of the charged ion in the ion mobility spectrometer can only be simulated by theoretical calculation, and the charged ion position under the ion mobility spectrometer can be easily and conveniently detected.

To this end, the present invention provides a method for tracing a moving ion distribution in an ion mobility spectrometer, comprising the following technical steps: using an ion having luminescent properties as an ion sample replacement step for the tracer ion under the ion mobility spectrometer; The ionization method of its luminescent property acts on the tracer ion to reach the standard for reproducing the original ion motion trajectory under the action of the ion mobility spectrometer, and sends the traceable ion to the ionization injection of the ion mobility spectrometer to be tested. (Ion processing) step; a collection step of collecting ions at a moving cross section of the tracer ion without affecting (using a non-conductive material) ion mobility spectrometer; collecting the ions on the ion development plate by optical means Luminescent tracer ions generate luminescence to obtain the cross-section ion Development step of distribution.

The ion mobility spectrometer refers to a trace substance detecting instrument that performs ion separation and determination using the difference in ion drift time.

The luminescent property in the ion replacement step means that the substance has a property of being excited by the absorbed energy and transitioning to the excited state (unsteady state) in the process of returning to the ground state, releasing energy in the form of light.

The ionization method that acts on the tracer ions in the ionization injection (ion processing) step without affecting the luminescence characteristics thereof includes that the cross section to be measured is an ion transfer tube section to be analyzed perpendicular to the direction of ion movement. It is the standard that can reproduce the conditions of the original ion motion trajectory under the action of the specified ion mobility spectrometer environment. The cross section of the tracer ion in the collecting step may be an ion transfer tube cut surface to be analyzed perpendicular to the direction of ion movement; the specific measurement position may be determined according to requirements.

The ion development plate of the enrichment step comprises an ion development plate which refers to a plate having a special shape design which does not affect the electric field distribution of the ion mobility spectrometer, including a microporous paperboard, a microporous glass plate and a microporous rubber plate;

The developing step optical means that the tracer ions collected on the developing plate are irradiated with excitation light in accordance with the excitation wavelength of the tracer ions to emit the luminescent photons. A light-emitting position map was obtained on the surface of the developing plate.

The invention proposes that the combination of the illuminating trace mode and the charged ion motion under the ion mobility spectrometer can more intuitively and practically grasp the position distribution of the charged ions under the ion mobility spectrometer.

DRAWINGS

1 is a structural diagram of an ion mobility spectrometer obtained by a specific embodiment of the present invention;

2A, 2B, and 2C are cross-sectional ion distribution diagrams of an ion mobility spectrometer obtained in accordance with an embodiment of the present invention; wherein FIG. 2A is a development map, and FIG. 2B is an XY plane distribution diagram, which is an XYZ triaxial diagram. In Figure 2C, the X and Y axes are position axes, the unit is the pixel size, and the Z axis and gray scale correspond to the number of received particles.

detailed description

The invention will now be further described with reference to the drawings in conjunction with the preferred embodiments.

Luminescent tracing is a characterization method and display method that can be used for biological probes, sewage treatment, heavy metal tracing, pH detection, etc. by marking a luminescent dye on a test object, illuminating the sample with a specific wavelength source, thereby causing the illuminating The labeled sample emits a different luminescence than the excitation band to reveal the sample of the marker. However, there are many technical problems to be solved for the trace of the moving ion distribution in the ion mobility spectrometer. This is explained in detail in the following embodiments.

Example 1

1 is a structural diagram of an ion mobility spectrometer obtained by a specific embodiment of the present invention, wherein 1 is an electrospray ion source, 2 is a migration tube, and 3 is an ion collection and development plate.

This embodiment includes the following steps:

(1) RHODAMINE 6G (Shanghai Jingchun Biochemical Technology Co., Ltd.) with luminescent properties was selected as the tracer of drift ion distribution in the cross section of the drift tube of the ion mobility spectrometer. RHODAMINE 6G is a yellow-green luminescent dye that is soluble in aqueous solvents such as water and methanol. Electrospray ion mobility spectrometer is a kind of detection method that makes a liquid sample into a gaseous charged ion by applying a high-voltage electric field, and then enters a drift region where a uniform electric field exists, and ion separation and qualitative determination of ions passing through the drift region. The drift region plays a key role in the separation of the sample. Therefore, in verifying the transmission efficiency of charged ions in the ion mobility spectrometer, it is urgent to adopt a simple and practical method without introducing additional interference. The ion transport cross-sectional distribution and the ion motion trajectory are detected.

(2) A solution of RHODAMINE 6G methanol (Shanghai Jingchun Biochemical Technology Co., Ltd.) at a concentration of 5 μM was placed. A RHODAMINE 6G methanol solution having a concentration of 5 μM was loaded using a syringe (Hamilton 1700 series). The front end of the injection injector was made of PEEK material with a double-pass serial diameter of 75 μm capillary and a voltage higher than the maximum voltage of the ion mobility spectrometer drift region of 6000V. The high potential RHODAMINE 6G methanol solution was electrosprayed at a capillary tip of the injection syringe in series at a injection rate of 5 μL/min into the drift tube of the ion mobility spectrometer.

(3) Using a glass slide cleaned with surface methanol and plasma, the length and width of the collected material are 60*20mm and the thickness is 4mm. The collected material is fixed with tape on the cross section of the drift tube where the ion distribution needs to be detected for 40s. The drift tube of the migration spectrometer is taken out, and the tracer ions are kept in the drift tube of the ion mobility spectrometer and are captured by the collected material during the time when the collected material is placed in the drift tube, and the pick-and-place process does not touch the surrounding environment.

(4) Using a pump laser with a wavelength of 532 nm as an excitation light source, the convex lens is expanded to obtain a circular uniform spot with a diameter of 50 mm. The collected material captured to the tracer ions is taken out and placed under the spot. The distribution of ions at the interface can be reproduced by using a CCD camera with a long-pass filter of 560 nm wavelength to obtain a spot distribution photo of the luminescent ions enriched on the collected paper.

2A, 2B and 2C are cross-sectional ion distribution diagrams of an ion mobility spectrometer obtained in accordance with an embodiment of the present invention; wherein Fig. 2A is a development map, Fig. 2B is an XY plane distribution diagram, and Fig. 2C is an XYZ triaxial diagram.

It should be noted that the tracer ions may also use other ions having fluorescent or phosphorescent properties. There is no requirement for charge and mass. As long as the particles with similar mobility are substituted, it is statistically discussed that the macroscopic cross section of the motion trajectory will not change.

In the above embodiments, an electrospray ionization source is used, but a soft ionization method such as a matrix-assisted laser desorption ionization source, and an ionization source and chemical ionization of the ultraviolet lamp can also be used.

Ion-collecting and developing plate If ion reflection occurs, scattering and the like will affect the measurement results. Therefore, it is necessary to select a developing plate that can fix ions and avoid diffuse reflection of ions. During the experiment, a fixed image of the ion track interface can be obtained by using a slide glass. The shape of the reception time pattern changes.

The ion-developing plate of the enrichment (collection) step includes an ion-developing plate finger having a special shape that does not affect the electric field distribution of the ion mobility spectrometer, such as a circular, square, and wire mesh that fits the ion mobility spectrum.

Since the particle charge is usually small, it generally does not significantly affect the collection of tracer sample ions for a short period of time. However, once the receiving plate carries a positive charge, the particles will not enrich at their surface, so the receiving plate should be protected from carrying a positive charge. In the actual process of this embodiment, the degree of enrichment increases with time, indicating that there is no positive charge formation on the surface of the receiving plate.

The above is a further detailed description of the present invention in combination with specific/preferred embodiments, and the specific embodiments of the invention are not limited to the description. It will be apparent to those skilled in the art that <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; It belongs to the scope of protection of the present invention.

Claims

A method for tracing a moving ion distribution in an ion mobility spectrometer, comprising the steps of:

S1, ion sample substitution: selecting an ion sample having luminescent properties as a trace ion sample of the ion mobility spectrometer;

S2, ionization injection: ionization method that does not affect the luminescence properties of the traced sample acts on the tracer ion to ionize the tracer sample to achieve the standard for reproducing the original ion motion trajectory under the action of the ion mobility spectrometer And feeding the traceable ions into the migration tube in the ion mobility spectrometer to be tested for migration;

S3, collecting: placing an ion collecting and developing plate at a section to be tested that does not affect the ion mobility spectrometer, and capturing tracer sample ions that migrate to the cross-sectional position through the migration tube;

S4. Developing: The ion collecting and developing plate is taken out, developed, and the sample ions collected on the ion collecting and developing plate are irradiated, and the sample ion position distribution is obtained according to the light intensity distribution.
The method for tracing a moving ion distribution in an ion mobility spectrometer according to claim 1, wherein the luminescent property of step S1 is that the substance is excited by the absorbed energy and transitions to the excited state in the process of returning to the ground state, The form of light releases energy.
A method of tracing a moving ion distribution in an ion mobility spectrometer according to claim 2, wherein the luminescence property is laser induced fluorescence.
The method for tracing a moving ion distribution in an ion mobility spectrometer according to claim 1, wherein the soft ionization method of the step S2 that does not affect the luminescence property of the tracer ion comprises an electrospray ionization source and an ultraviolet lamp. Ionization source, matrix-assisted laser desorption ionization source and chemical ionization.
The method for tracing a moving ion distribution in an ion mobility spectrometer according to claim 1, wherein the cross section to be measured in step S3 is a cross section of the ion mobility shift drift tube to be analyzed perpendicular to the direction of ion motion.
The method for tracing a moving ion distribution in an ion mobility spectrometer according to claim 1, wherein the ion developing plate of step S3 refers to a plate material that does not affect the electric field distribution of the ion mobility spectrometer, including cardboard, glass plate, rubber sheet. .
The method for tracing a moving ion distribution in an ion mobility spectrometer according to claim 1, wherein the developing means of step S4 refers to irradiating the tracer ions collected on the developing plate with excitation light in accordance with the excitation wavelength of the tracer ion. It emits luminescent photons and obtains a map of the illuminating position on the surface of the developing plate.
The method for tracing a moving ion distribution in an ion mobility spectrometer according to claim 1, wherein The ion collecting and developing plate in step S3 is made of a non-conductive material.
The method for tracing a moving ion distribution in an ion mobility spectrometer according to claim 1, wherein the ion collecting and developing plate in step S3 selects a developing plate capable of fixing ions and avoiding diffuse reflection of ions, and has a circular shape. , square or wire mesh.
A method of tracing a moving ion distribution in an ion mobility spectrometer according to claim 1, wherein said ion sample has a fluorescent or phosphorescent characteristic in step S1.